Reciprocating ratchet mechanism

ABSTRACT

A pair of opposed ratchets are mounted for reciprocation along a predetermined path, and a pawl alternately engages each ratchet along its entire length. The pawl prevents reversal of direction of the ratchets until the path in each direction has been traversed. A set of channels guides the relative movement of the pawl and ratchets through a sequence of paths to effect the operation of the mechanism.

States Patent 5] Mar. 14, 1972 RECIPROCATING RATCHET MECHANISM LeonardF. Kemp, Rochester, N.Y.

Eastman Kodak Company, Rochester, N.Y.

Filed: June 17, 1970 Appl. No.: 46,939

Inventor:

Assignee:

U.S. Cl ..74/17.5 Int. Cl ...Fl6l1 57/06 Field of Search ..74/ l 7.5

References Cited UNITED STATES PATENTS Ohmer ..74/1 7.5

2,740,245 4/1956 Lochner ..74/l7.5X

Primary ExaminerMilton Kaufman An0rney-Robert W. Hampton and D. PeterHochberg [57] ABSTRACT A pair of opposed ratchets are mounted forreciprocation along a predetermined path, and a pawl alternately engageseach ratchet along its entire length. The pawl prevents reversal ofdirection of the ratchets until the path in each direction has beentraversed. A set of channels guides the relative movement of the pawland ratchets through a sequence of paths to effect the operation of themechanism.

7 (Ilairns, 5 Drawing Figures 2 Sheets-Sheet l LEONARD F. KAMP INVENTOR.

ATTORNEYS 2 Sheets-Sheet 2 .J-LEONARD F. KAMP i INVENTOR.

ATTORNEYS RECIIPROCATING RATCI'IET MECHANISM CROSS-REFERENCES TO RELATEDAPPLICATIONS Reference is made to commonly assigned copending U.S.Patent application Ser. No. 46,856, entitled Mechanism for Use in aCamera for Exposing and Initiating the Processing of PhotographicUnits," filed in the name of Leonard Kamp on even date herewith.

BACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to reciprocating mechanisms having means for preventing reversalof direction only after a prescribed path has been traversed. Moreparticularly, the present invention relates to pawl and ratchetmechanisms which permit reciprocating movement of a driven member, butwith path reversal possible only when the pawl mechanism reaches apredetermined position on the ratchet mechanism.

2. Description of the Prior Art Existing pawl and ratchet mechanismswhich prevent reversal of the direction of travel of a reciprocatingmember prior to completion of a predetermined path of travel, generallycomprise one or more pawl devices for engaging a single ratchet. Inorder to provide for reversal of the direction of travel of the pawlrelative to the ratchet, a space must be provided at the end of theratchet to permit the pawl device to be adjusted, such as by flippingover, to engage the ratchet in such a fashion as to prevent travel inthe old direction while permitting travel in a new direction. A small ofovertravel of the pawl carrier relative to the ratchet in each directionmust be provided in such prior art systems to make reversal of directionof the carrier possible. This overtravel results in objectionable playin the carrier at the ends of the path. Furthermore, prior mechanisms ofthis type necessitate interruptions in the teeth at both ends of theratchet, thus increasing the length of the ratchet relative to thelength of the path of the pawl carrier.

SUMMARY OF THE INVENTION The present invention provides a simple deviceincluding a reciprocating member, and means for preventing reversal ofdirection of the member prior its transversal of a predetermined path.In a preferred embodiment of the present inven tion, a pair of ratchetsare carried by a slide in an opposed, parallel relationship, and theybox in a pawl. The slide is reciprocatively displaceable relative to thepawl, the pawl being urged into engagement with alternate ratchets forrespective directions of travel. The slide is sequentially guided alongits path of travel relative to the pawl by a set of channels. Uponreaching a predetermined position relative to the slide, the pawl isdisengaged from one ratchet and moved into engagement with the otherratchet and moved into engagement with the other ratchet to permitreturn travel of the slide.

An object of the present invention is to provide an improvedreciprocating ratchet mechanism which is simple and compact.

Another object of the present invention is the provision of areciprocating pawl and ratchet mechanism wherein a pawl is engaged witha ratchet throughout the reciprocating movement, and wherein overtravelfor direction reversal is prevented.

Still another object of the present invention is the provision of amechanism of the type described which is easy to operate. The invention,an its objects and advantages, will become more apparent in the detaileddescription of the preferred embodiment presented below.

The invention is especially suitable for use in a camera which effectsboth the exposure and processing of slide transparencies, such as thatdisclosed in commonly assigned U.S. Application Ser. No. 675,597, howU.S. Pat No. 3,541,937 entitled Camera and Method for Exposing andDeveloping Slide Transparency Units," filed in the name of Hubert Nerwinon Oct. l6, I967, wherein photographic units are successively drawn froma supply chamber to an exposure chamber, and exposed units aresuccessively processed and pushed out of the camera. The invention isalso suitable for use in a camera wherein fresh film must be advanced byexactly a full frame to prevent either double exposures or unusedsegments of film between exposures. While these uses suggest themselves,one skilled in the art will readily recognize that the invention lendsitself to any application wherein anti-reversal reciprocating movementis desired.

The invention, and its objects and advantages, will become more apparentin the detailed description of the preferred embodiment presented below.

BRIEF DESCRIPTION OF THE DRAWINGS In the detailed description of thepreferred embodiment of the invention presented below, reference is madeto the accompanying drawing, in which:

FIG. I is a partially sectioned view of the back of a camera wherein aslide carrying a ratchet mechanism according to the invention is shownat one end of its path of travel relative to an associated pawlmechanism;

FIG. 2 illustrates the camera of FIG. l with the slide at anintermediate point in one direction of its path of travel;

FIG. 3 is a section through the line 3-3 in FIG. 1;

FIG. 4 shows the camera of FIGS. l and 2 with the slide at the oppositeend of its path from that shown in FIG. 1; nd

FIG. 5 is a view of the interior side of the camera door employing theinvention, and is taken at the line 5-5 in FIG. 3

DESCRIPTION OF THE PREFERRED EMBODIMENT Because cameras are well known,the present description will be directed in particular to elementsforming part of, or cooperating more directly with, cameras inaccordance with the present invention. Specifically, the descriptionwill be directed to cameras for exposing and processing photographicunits, such as that disclosed in above-cited U.S. Application Ser. No.675,597 now U.S. Pat. No. 3,541,937. It is to be understood that cameraelements not specifically shown or described may take various forms wellknown to those skilled in the art.

Referring to FIGS. l and 3, the interior of the door of a camera 1includes a latch 2 having a pair of slots 4 through which studs 6 extendfrom camera I to permit limited vertical movement of the latch. Latch 2includes a lug 8 which is shown engaged in a slot 10 on a slide 12.Latch 2 also carries a pawl 14 which is mounted on a pivot 16. Latch 2is urged upward by a torsion spring 18. Slide 12 includes a pair ofopposed, parallel ratchets 22 and 24. A surface 20 of pawl 14 is urgedby a torsion spring 19 on latch 2 into engagement with the first ofteeth 21 in ratchet 22. Latch 2 has a numeral l and an arrow providedthereon which. indicated that depres sion of latch 2 by a button 3 isthe first step in a sequence of operational steps to be describedsubsequently.

Also shown in FIGS. 1 and 3 is a handle 26 which, when moved to theright as directed by the numeral 2" and the accompanying arrow, urgesslide 12 to the right. The latter directional figures are embossed on abearing plate 13 for slide 12 mounted on the camera beneath the slide12, and are visible through an opening in the camera casing. It will beob served that the depression of button 3 urges lug 8 out of slot andinto contact with the top of a thin spring 28, and that the subsequentmovement of button 26 to the right causes the irreversible movement ofslide 12 and the parts included thereon to the right.

Slide 12 further includes slots 30 and 32 which are parallel to ratchets22 and 24. When latch 2 is moved downward and slide 12 is urged to theright as described above, spring 28 guides lug 8 into slot 30. Theposition of pivot 16 is such that when lug 8 travels in slot 30, surface20 of pawl 14 is maintained in engagement with the teeth 21. Thus, inFIG. 2, slide 112 is shown at an intermediate point in its path oftravel with lug 8 engaged in slot 30, and surface 20 of pawl 14 engagedin teeth 21 of ratchet 22. Also, the movement of slide 12 to the rightcauses the concealment of the instructional numeral 4 carried on a partof slide 12 previously covered by the camera casing.

As slide 12 is urged to the right, lug 8 eventually reaches the end ofslot 30 and enters notch 29 at the end of slots 30 and 32. A numeral 3with an accompanying arrow printed on a depression 33 is a portion ofthe camera casing which was initially concealed by button 3, and whichwas displayed upon the depression of latch 2 in the first step,indicates that the third operational step requires the furtherdepression of latch 2 by means of button 3. This forces lug 8 under athin spring 34 as shown in FIG. 4. In addition, as pawl 14 is disengagedfrom teeth 21 with the depression of latch 2, it is subjected to thecounterclockwise force of spring 19, and surface 36 of pawl 14 is thusput in engagement with teeth 38 of ratchet 24. The subsequentirreversible movement of slide 12 to the left as instructed by numeral 4causes lug 8 on latch 2 to travel along slot 32 while pawl 14 ismaintained in engagement with teeth 38 of ratchet 24. When the leftwardpath of travel is completed, lug 8 leaves slot 32. Spring 18 urges latch2 upwardly, lug 8 is moved past spring 28 into notch 10. The mechanismhas returned to the initial arrangement depicted in FIG. 1 It should benoted that when lug 8 is moved past springs 34 and 28 respectively, lug8 cannot be moved past those elements causes them to obstruct suchreverse movement.

When incorporated in a camera according to previously referencecopending U.S. Application Ser. No. 675,597, now U.S. Pat. No.3,514,937, Ser, No. 46,856, .the ratchet mechanism is used to effect thereciprocation of carriage 40 shown in FIGS. 3 and 5. Carriage 40comprises a claw assembly 42 for engaging and transporting freshphotographic units from a storage chamber to an exposure chamber in themain body portion of camera 1, and a roller assembly 44 for rupturingpods of processing solution carried by the units to effect theprocessing of exposed units. The claw and roller assemblies are mountedon a resilient ember 46 which is attached to the forward side of slide12 by means of screws 48, the exterior of the door being considered theback of the camera. Carriage 40 is successively reciprocated in a pathacross the inside of the camera door to accomplish its functions.Accordingly, after an exposure has been made, the photographer depressesthe button 3 and moves handle 26 to the right (FIG. 2) to move slide 12,hence carriage 40, to the left (FIG. to rupture a pod on an exposedphotographic unit and, at the end of the initial direction of travel, toengage a fresh unit. Button 3 is then depressed further and handle 26 ismoved to the left (FIG. 4), to drive carriage 40 to the right (FIG. 5),thereby taking a fresh unit to the exposure area and pushing the exposedtransparency through an exit in the camera (not shown).

The invention has been described in detail with particular reference tothe preferred embodiment thereof, but it will be understood thatvariations and modifications can be effected within the spirit an scopeof the invention.

I claim:

1. A reciprocating ratchet mechanism comprising:

a pawl mechanism;

a member mounted for reciprocating movement relative to said pawlmechanism in first and second directions between first and second endpositions, said member including first and second opposed ratchets, saidpawl mechanism being alternately movable into engagement with said firstand second ratchets when said member moves in said first and seconddirections respectively, to prevent said member from changing itsdirection of travel at a position between said end positions;

control means for maintaining said pawl mechanism in engagement withsaid first ratchet during movement of said member in said firstdirection, for maintaining said pawl mechanism in engagement with saidsecond ratchet during movement of said member in said second direction,and for permitting movement of said pawl mechanism between engagementswith said first and second ratchets at said end positions.

2. A reciprocating ratchet mechanism comprising:

a housing;

a member mounted in said housing for reciprocating movement in first andsecond directions along a path from a first end position to a second endposition, and back to said first end position, respectively, said memberincluding said first and second ratchets;

pawl means for controlling movement of said reciprocable member, saidpawl means including first and second pawl surfaces, said first pawlsurface being engageable with said first ratchet to prevent movement ofsaid reciprocable member in said second direction while permittingmovement of said member in said first direction, and said second pawlsurface being engageable with said second ratchet to prevent movement ofsaid reciprocable member in said first direction while permittingmovement of said member in said second direction;

pawl control means mounted in said housing and coupled to said pawlmeans for movement transverse to said first and second directionsbetween a first control position in which said first pawl surface is inengagement with said first ratchet, and a second control position inwhich said second pawl surface is in engagement with said secondratchet; and

guide means carried by said reciprocating member for controlling thetransverse movement of said pawl control means, wherein said guide meansdefines a path for said pawl control means between said first and secondcontrol positions in response to movement of said reciprocating memberto said end positions, and for maintaining said control means in saidfirst and second control positions during movement of said reciprocatingmember in said first and second directions, respectively.

3. In a camera for exposing and initiating the processing ofphotographic units and including a carriage reciprocable between firstand second positions in the camera for transporting photographic unitsin the camera, a mechanism for operating the carriage, said mechanismcomprising:

a. a slide, reciprocable between said first and second positions along afirst path;

b. a latch, reciprocable between third and fourth positions along asecond path transverse to said first path;

c. means for preventing reversal of the direction of travel of saidslide at a point between said first and second positions, said meanscomprising:

a pair of opposed ratchets carried by said slide and having a lengthequal to the distance between said first and second positions;

pawl means carried by said latch for engaging one of said ratchets whensaid slide is between said first and second positions;

a pair of adjacent channels, each parallel with a corresponding ratchet,carried by one of said slide and latch, and end channels connectingadjacent ends of said channels and delimiting said channels to a lengthcorresponding to that of said ratchets;

a lug carried by the other of said slide and latch, for engaging saidchannels and end channels and moving along the length thereof;

wherein said channels and lug are positioned on said slide and latchrelative to said pawl and ratchets to maintain said pawl means inengagement with alternate ratchets when said lug is engaged withalternate channels.

4. A mechanism according to claim 3 wherein:

said ratchets are parallel, said channels and end channels are carriedby said slide, and said channels parallel with said ratchets; said lugis carried by said latch; and said pawl means comprises:

a pawl having two opposite end portions for engaging respectiveratchets, said pawl being pivotally n s n an a..-

mounted on said latch at a position intermediate said end portions, and

means for urging respective end portions into engagement with acorresponding one of said ratchets when said lug is engaged with thechannel corresponding to said corresponding ratchet.

5. A mechanism according to claim 4 further comprising means for urgingand guiding said latch to a fifth position in which said lug assumes aposition blocking said slide from movement and retains said slide insaid first position.

6. A mechanism according to claim 5 further including:

means for moving said latch from said fifth position to said thirdposition wherein said lug is in alignment with a first of said channels;

means for moving said slide from said first position towards said secondposition, such that said lug is engaged with said first channel, and afirst of said pawl end portions is LII engaged with a first of saidratchets, which ratchet corresponds to said first channel, and formoving said slide from said second position towards said first position,such that said lug is engaged with said second channel and the second ofsaid pawl end portions is engaged with the second of said ratchets,which ratchet corresponds to said second channel; and

means for moving said latch to said fourth position and for moving saidlug along the second of said end channels, in which fourth position saidlug is in alignment with the second of said channels.

7. A mechanism according to claim 6 further comprising means responsiveto the movement of said latch to said fourth position for preventingsaid latch from returning to said third position.

1. A reciprocating ratchet mechanism comprising: a pawl mechanism; a member mounted for reciprocating movement relative to said pawl mechanism in first and second directions between first and second end positions, said member including first and second opposed ratchets, said pawl mechanism being alternately movable into engagement with said first and second ratchets when said member moves in said first and second directions respectively, to prevent said member from changing its direction of travel at a position between said end positions; control means for maintaining said pawl mechanism in engagement with said first ratchet during movement of said member in said first direction, for maintaining said pawl mechanism in engagement with said second ratchet during movement of said member in said second direction, and for permitting movement of said pawl mechanism between engagements with said first and second ratchets at said end positions.
 2. A reciprocating ratchet mechanism comprising: a housing; a member mounted in said housing for reciprocating movement in first and second directions along a path from a first end position to a second end position, and back to said first end position, respectively, said member including said first and second ratchets; pawl means for controlling movement of said reciprocable member, said pawl means including first and second pawl surfaces, said first pawl surface being engageable with said first ratchet to prevent movement of said reciprocable member in said second direction while permitting movement of said member in said first direction, and said second pawl surface being engageable with said second ratchet to prevent movement of said reciprocable member in said first direction while permitting movement of said member in said second direction; pawl control means mounted in said housing and coupled to said pawl means for movement transverse to said first and second directions between a first control position in which said first pawl surface is in engagement with said first ratchet, and a second control position in which said second pawl surface is in engagement with said second ratchet; and guide means carried by said reciprocating member for controlling the transverse movement of said pawl control means, wherein said guide means defines a path for said pawl control means between said first and second control positions in response to movement of said reciprocating member to said end positions, and for maintaining said control means in said first and second control positions during movement of said reciprocating member in said first and second directions, respectively.
 3. In a camera for exposing and initiating the processing of photographic units and including a carriage reciprocable between first and second positions in the camera for transporting photographic units in the camera, a mechanism for operating the carriage, said mechanism comprising: a. a slide, reciprocable between said first and second positions along a first path; b. a latch, reciprocable between third and fourth positions along a second path transverse to said first path; c. means for preventing reversal of the direction of travel of said slide at a point between said first and second positions, said means comprising: a pair of opposed ratchets carried by said slide and having a length equal to the distance between said first and second positions; pawl means carried by said latch for engaging one of said ratchets when said slide is between said first and second positions; a pair of adjacent channels, each parallel with a corresponding ratchet, carried by one of said slide and latch, and end channels connecting adjacent ends of said channels and delimiting said channels to a length correspondiNg to that of said ratchets; a lug carried by the other of said slide and latch, for engaging said channels and end channels and moving along the length thereof; wherein said channels and lug are positioned on said slide and latch relative to said pawl and ratchets to maintain said pawl means in engagement with alternate ratchets when said lug is engaged with alternate channels.
 4. A mechanism according to claim 3 wherein: said ratchets are parallel, said channels and end channels are carried by said slide, and said channels parallel with said ratchets; said lug is carried by said latch; and said pawl means comprises: a pawl having two opposite end portions for engaging respective ratchets, said pawl being pivotally mounted on said latch at a position intermediate said end portions, and means for urging respective end portions into engagement with a corresponding one of said ratchets when said lug is engaged with the channel corresponding to said corresponding ratchet.
 5. A mechanism according to claim 4 further comprising means for urging and guiding said latch to a fifth position in which said lug assumes a position blocking said slide from movement and retains said slide in said first position.
 6. A mechanism according to claim 5 further including: means for moving said latch from said fifth position to said third position wherein said lug is in alignment with a first of said channels; means for moving said slide from said first position towards said second position, such that said lug is engaged with said first channel, and a first of said pawl end portions is engaged with a first of said ratchets, which ratchet corresponds to said first channel, and for moving said slide from said second position towards said first position, such that said lug is engaged with said second channel and the second of said pawl end portions is engaged with the second of said ratchets, which ratchet corresponds to said second channel; and means for moving said latch to said fourth position and for moving said lug along the second of said end channels, in which fourth position said lug is in alignment with the second of said channels.
 7. A mechanism according to claim 6 further comprising means responsive to the movement of said latch to said fourth position for preventing said latch from returning to said third position. 